Thanks very much for the info everyone. I have been a bit pre-occupied this week (see Lost Cat thread in chitchat!), so I haven't been thinking so much about the hens. I almost came to the conclusion that life would be better without any animals, but I know that won't last, I haven't the temperment or background to avoid having pets!
I was intending to use chicken wire for the run top, as the space is 1.6m, and I found you could get 1.8m wide. As 3 sides, almost 4 if you count the greenhouse, would be solid, I felt it would get too hot in summer if I roofed the whole lot, but the rain will be an issue on bedding.
I found your comments very useful sunflower, I was thinking of using the horse bedding stuff on the floor, and we can lay some paving or something as a hard surface. 3-4 weekly cleaning of the run sounds reasonable. It is the smell I am particularly concerned about, because our gardens are small, and we have people backing onto us, as well as at the sides.
I was intending ex-batts, but my daughter has her heart set on a Mrs Pepperpot from the Omlet website, as they are black. As far as I remember from when my Mum worked at a battery farm (horrible place, I hated going there, I was about 10, and saw the conditions, and smelled the smell, first hand), they are brown. Perhaps I can get some of each? She was dead against any to start with, until I explained they would become pets, and she could have one of her own. Mind you she was very up front about not cleaning them out!

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